1. Technical Field
The invention is directed to the field of lighting and, more particularly, to a compact fluorescent lamp which is adapted to be installed in an Edison socket of an incandescent floor lamp fixture, table lamp fixture or the like.
2. Background of the Related Art
It is well known that compact fluorescent lamps are overall more cost efficient than incandescent lamps. Although compact fluorescent lamps are generally more expensive to purchase than incandescent lamps, they are more energy efficient and longer lasting, and thus provide long-term cost savings.
There has accordingly been an effort to increase the use of compact fluorescent lamps in new lighting fixtures and in retrofit applications. Although partially successful, the former effort has been limited by the higher purchase cost of the fluorescent lamps and because the savings that these lamps provide in terms of lower energy costs may not be realized in the short term.
The effort to install compact fluorescent lamps in retrofit applications has been limited by factors such as lamp orientation, lumen output and lamp fixture size. These factors have limited the use of compact fluorescent lamps in lighting fixtures such as floor and table lamps, where there remains a great retrofit potential.
Regarding lamp orientation, for table lamp applications, the known fixtures typically locate the lamp in a vertical plane, either in the so-called lamp "base-up" or "base-down" orientation. The vast majority of the fixtures in the market today include Edison screw-in type sockets and are oriented vertically.
It is known, however, that the optimal orientation of such compact fluorescent lamps is horizontal and not vertical. Some of the known recessed fixtures utilize a horizontal orientation of the lamp, but such fixtures are usually not suited for retrofit products.
For table lamp applications utilizing a twin or quad-type of compact fluorescent lamp, in addition to being base-down, the light must be reflected off the fixture lamp shade and then downward before it is emitted into the room space. Accordingly, the light output losses have been great in such applications based on the optimization ratings of the lamp manufacturers.
Regarding lamp size, in conventional table lamp fixtures, the configuration of the harp suspending the lamp shade has severely limited the applicability of the known self-ballasted compact fluorescent lamps. Such known lamps have been both too wide and too long to fit within the wireforms of the harps. These size factors have greatly limited the ability of compact fluorescent lamps to be used in retrofit applications and, in particular, applications which have required a high-lumen output such as 75 and 100 watt, or a greater incandescent equivalent.
Even where retrofit applications have been possible using the known compact fluorescent lamps, there has been the further problem that the lamps are frequently stolen and replaced with the less efficient incandescent lamps. This problem, known as "snap-back," has been reduced by incorporating theft protective features in the compact fluorescent lamps and in the socket adapters which have enabled the use of these lamps in Edison sockets.